Various connection devices comprising a ferrule with a capillary channel have already been proposed.
Document FR-A-2 657 865, for example, describes an optical fiber connection endpiece that includes a capillary channel together with an entry cone formed by machining in each endpiece. To connect two optical fibers together, they are placed in respective ones of the above-mentioned endpieces, with engagement of the fibers in the endpieces being facilitated by the entry cones. Thereafter, the optical fibers are secured in their respective endpieces by means of a polymerizable adhesive, and the two endpieces are assembled together and brought into alignment in a complementary sleeve.
Variant endpieces having capillary channels associated with entry cones suitable for receiving respective optical fibers are described in Documents WO-A-87 01464 and JP-A-58 9116, for example.
Those known optical fiber connection devices, each comprising two ferrules associated with respective optical fibers do not give full satisfaction.
In particular, the alignment of the two ferrules in a complementary sleeve is not always sufficiently accurate to obtain satisfactory alignment of the fibers, and as a result non-negligible losses occur in the coupling of light energy.
Document U.S. Pat. No. 3,944,328 describes another variant of a ferrule, made by molding, e.g. using epoxy resin, and including a capillary channel that is provided at both ends with an entry cone. A single ferrule can thus receive respective ends of two optical fibers. That technique avoids any need to subsequently align two ferrules each receiving one fiber.
Nevertheless, the technique described in Document U.S. Pat. No. 3,944,328 does not give full satisfaction, either. When a ferrule is made by molding, it is not always possible to obtain a satisfactory capillary channel, i.e. a capillary channel having sufficient dimensional accuracy to obtain satisfactory alignment of the fibers.
Document EP-A-0 272 112 describes an optical fiber connector that comprises a ferrule and a heat-shrink cover that contains a sealant. The sealant is confined on the ferrule 2 when the cover 8 is shrunk. However, in that system, where the confinement material is pressed against the ferrule by the heat-shrink cover, it is not possible to define very accurate entry cones for the optical fibers, i.e. entry cones that coincide exactly with the capillary channel of the ferrule.
The main object of the present invention is to eliminate the drawbacks of the prior art.